<?php
/*

 * 模式四种分页模式：
   require_once('../libs/classes/page.class.php');
   $page=new page(array('total'=>1000,'perpage'=>20));
   echo 'mode:1<br>'.$page->show();
   echo '<hr>mode:2<br>'.$page->show(2);
   echo '<hr>mode:3<br>'.$page->show(3);
   echo '<hr>mode:4<br>'.$page->show(4);
   开启AJAX：
   $ajaxpage = new page(array('total'=>1000,'perpage'=>20,'ajax'=>'ajax_page','page_name'=>'test'));
   echo 'mode:1<br>'.$ajaxpage->show();
   采用继承自定义分页显示模式：
   
 */
class page {
	 /**
	  * config ,public
	  */
	 var $page_name = "page";//page标签，用来控制url页。比如说xxx.php?PB_page=2中的PB_page
	 var $next_page = '>';//下一页
	 var $pre_page  = '<';//上一页
	 var $first_page = 'First';//首页
	 var $last_page  = 'Last';//尾页
	 var $pre_bar    = '<<';//上一分页条
	 var $next_bar   = '>>';//下一分页条
	 var $format_left  = '[';
	 var $format_right = ']';
	 var $is_ajax    = false;//是否支持AJAX分页模式
	 var $is_rewrite = true;//是否启动url重写分页模式
	 var $totalcount  = 0;
	 var $nowpage ;
	 var $perpage = 0;
	 
	 /**
	  * private
	  *
	  */ 
	 var $pagebarnum = 10;//控制记录条的个数。
	 var $totalpage  = 0;//总页数
	 var $ajax_action_name = '';//AJAX动作名
	 var $nowindex = 1;//当前页
	 var $url    = "";//url地址头
	 var $offset = 0;
 
	/**
		* constructor构造函数
		*
		* @param array $array['total'],$array['perpage'],$array['nowindex'],$array['url'],$array['ajax']...
	*/
	function page($array) {
		if(is_array($array)) {
			if(!array_key_exists('total',$array))
				$this->error(__FUNCTION__,'need a param of total');
			$this->totalcount = $total = intval($array['total']);
			$perpage  = (array_key_exists('perpage',$array))  ? intval($array['perpage']):10;
			$this->nowpage = $nowindex = (array_key_exists('nowindex',$array)) ? intval($array['nowindex']):'';
			$url      = (array_key_exists('url',$array)) ? $array['url'] : '';
		} else {
			$total    = 0;
			$perpage  = 10;
			$nowindex = '';
			$url      = '';
		}
		if( (!is_int($total)) || ($total < 0) )
			$this->error(__FUNCTION__,$total.' is not a positive integer!');
		if( (!is_int($perpage)) || ($perpage <= 0) )
			$this->error(__FUNCTION__,$perpage.' is not a positive integer!');
		if(!empty($array['page_name']))
			$this->set('page_name',$array['page_name']);//设置pagename
		$this->_set_nowindex($nowindex);//设置当前页
		$this->_set_url($url);//设置链接地址
		$this->perpage = $perpage;
		$cont  = $total / $perpage;	
		$cont2 = $total % $perpage;
		if( $cont > 1 && $cont2 == 0 ) {
			$this->totalpage = floor($cont);
		}
		elseif( $cont2 > 0) {
			$this->totalpage = floor($cont)+1;
		}	
		$this->offset    = ($this->nowindex-1) * $this->perpage;
		if(!empty($array['ajax']))
			$this->open_ajax($array['ajax']);//打开AJAX模式
	}
	/*
	* 设定类中指定变量名的值，如果改变量不属于这个类，将throw一个exception
	*
	* @param string $var
	* @param string $value
	*/
	function set($var,$value) {
		if(in_array($var,get_object_vars($this)))
			$this->$var=$value;
		else
			$this->error(__FUNCTION__,$var." does not belong to PB_Page!");
	}
	/**
	* 打开倒AJAX模式
	*
	* @param string $action 默认ajax触发的动作。
	*/
	function open_ajax($action) {
		$this->is_ajax = true;
		$this->ajax_action_name = $action;
	}
	/**
	* 获取显示"下一页"的代码
	* 
	* @param string $style
	* @return string
	*/
	function next_page($style='') {
		if($this->nowindex<$this->totalpage) {
			return $this->_get_link($this->_get_url($this->nowindex+1),$this->next_page,$style);
		}
		return '<span class="'.$style.'">'.$this->next_page.'</span>';
	}

	/**
	* 获取显示“上一页”的代码
	*
	* @param string $style
	* @return string
	*/
	function pre_page($style='') {
		if($this->nowindex > 1) {
			return $this->_get_link($this->_get_url($this->nowindex-1),$this->pre_page,$style);
		}
		return '<span class="'.$style.'">'.$this->pre_page.'</span>';
	}

	/**
	* 获取显示“首页”的代码
	*
	* @return string
	*/
	function first_page($style='') {
		if($this->nowindex==1) {
			return '<span class="'.$style.'">'.$this->first_page.'</span>';
		}
		return $this->_get_link($this->_get_url(1),$this->first_page,$style);
	}

	/**
	* 获取显示“尾页”的代码
	*
	* @return string
	*/
	function last_page($style=''){
		if( $this->nowindex == $this->totalpage ) {
			return '<span class="'.$style.'">'.$this->last_page.'</span>';
		}
		return $this->_get_link($this->_get_url($this->totalpage),$this->last_page,$style);
	}

	function nowbar($style='',$nowindex_style='') {
		$plus = ceil( $this->pagebarnum / 2 );
		if($this->pagebarnum - $plus + $this->nowindex > $this->totalpage ) {
			$plus = ($this->pagebarnum - $this->totalpage + $this->nowindex);
		}
		$begin = $this->nowindex - $plus + 1;
		$begin = ( $begin >= 1) ? $begin : 1;
		$return = '';
		for($i = $begin; $i < $begin + $this->pagebarnum ; $i++) {
			if( $i <= $this->totalpage ) {
				if( $i != $this->nowindex ) {
					$return .= $this->_get_text($this->_get_link($this->_get_url($i),$i,$style));
				} else {
					$return .= $this->_get_text('<span class="'.$nowindex_style.'">'.$i.'</span>');
				}
			} else {
				break;
			}
			$return .= "\n";
		}
		unset($begin);
		return $return;
	}
	/**
	* 获取显示跳转按钮的代码
	*
	* @return string
	*/
	function select() {
		$return = '<select id="PB_Page_Select" onChange="window.location.href = \''.$this->url.'\'+this.value;"  >';
		for( $i=1 ; $i <= $this->totalpage ; $i++ ){
			if( $i == $this->nowindex ) {
				$return .= '<option value="'.$i.'" selected>'.$i.'</option>';
			} else {
				$return .= '<option value="'.$i.'">'.$i.'</option>';
			}
		}
		unset($i);
		$return .= '</select>';
		return $return;
	}

	/*
	* 获取mysql 语句中limit需要的值
	*
	* @return string
	*/
	function offset() {
		return $this->offset;
	}

	/**
	* 控制分页显示风格（你可以增加相应的风格）
	*
	* @param int $mode
	* @return string
	*/
	function show($mode=1) {
		
		$str = "共 {$this->totalcount} 条记录  ";  
		if($this->nowpage > 0)
			$str .= " 第{$this->nowpage}/{$this->totalpage}页 ";
		switch ($mode){
			case '1':
				$this->next_page = '下一页';
				$this->pre_page  = '上一页';
				return $str . $this->pre_page().'&nbsp;&nbsp;'.$this->nowbar().'&nbsp;'.$this->next_page().'&nbsp;&nbsp;'.'第'.$this->select().'页';
				break;
			case '2':
				$this->next_page  = '下一页';
				$this->pre_page   = '上一页';
				$this->first_page = '首页';
				$this->last_page  = '尾页';
				return $str . $this->first_page().$this->pre_page().'[第'.$this->nowindex.'页]'.$this->next_page().$this->last_page().'第'.$this->select().'页';
				break;
			case '3':
				$this->next_page  = '下一页';
				$this->pre_page   = '上一页';
				$this->first_page = '首页';
				$this->last_page  = '尾页';
				return $str .  $this->first_page().$this->pre_page().$this->next_page().$this->last_page();
				break;
			case '4':
				$this->next_page = '下一页';
				$this->pre_page  = '上一页';
				return $str .  $this->pre_page().$this->nowbar().$this->next_page();
				break;
			case '5':
				return $str .  $this->pre_bar.$this->pre_page().$this->nowbar().$this->next_page().$this->next_bar;
				break;
		}
	}
	/*----------------private function (私有方法)-----------------------------------------------------------*/
	/**
	* 设置url头地址
	* @param: String $url
	* @return boolean
	*/
	function _set_url($url="") {
		if(!empty($url)) {
			//手动设置
			$this->url = $url.((stristr($url,'?'))?'&':'?').$this->page_name."=";
		} else {
			//自动获取
			if(empty($_SERVER['QUERY_STRING'])) {
				//不存在QUERY_STRING时
				#如果开启了url重写
				if($this->is_rewrite) {
					$str = ereg_replace('(p)\/([0-9]{1,})$','',$_SERVER['REQUEST_URI']);
					$this->url = $str .'p/';
				} else {
					$this->url = $_SERVER['REQUEST_URI']."?".$this->page_name."=";
				}
			} else {
				if(stristr($_SERVER['QUERY_STRING'],$this->page_name.'=')) {
				//地址存在页面参数
					$this->url = str_replace($this->page_name.'='.$this->nowindex,'',$_SERVER['REQUEST_URI']);
					$last = $this->url[strlen($this->url)-1];
					if($last=='?'||$last=='&') {
						$this->url .= $this->page_name."=";
					} else {
						$this->url .= '&'.$this->page_name."=";
					}
				} else {
					$this->url = $_SERVER['REQUEST_URI'].'&'.$this->page_name.'=';
				}//end if    
			}//end if
		}//end if
	}

	/**
	* 设置当前页面
	*
	*/
	function _set_nowindex($nowindex) {
		if(empty($nowindex)) {
		//系统获取
			if(isset($_GET[$this->page_name])) {
				$this->nowindex = intval($_GET[$this->page_name]);
			}
		} else {
		//手动设置
		$this->nowindex = intval($nowindex);
		}
	}

	/**
	* 为指定的页面返回地址值
	*
	* @param int $pageno
	* @return string $url
	*/
	function _get_url($pageno=1) {
		return $this->url.$pageno;
	}

	/**
	* 获取分页显示文字，比如说默认情况下_get_text('<a href="">1</a>')将返回[<a href="">1</a>]
	*
	* @param String $str
	* @return string $url
	*/ 
	function _get_text($str) {
		return $this->format_left.$str.$this->format_right;
	}

	/**
	* 获取链接地址
	*/
	function _get_link($url,$text,$style='') {
		$style = (empty($style))?'':'class="'.$style.'"';
		if($this->is_ajax) {
		//如果是使用AJAX模式
			return '<a '.$style.' href="javascript:'.$this->ajax_action_name.'(\''.$url.'\')">'.$text.'</a>';
		} else {
			return '<a '.$style.' href="'.$url.'">'.$text.'</a>';
		}
	}
	/**
	* 出错处理方式
	*/
	function error($function,$errormsg) {
		die('Error in file <b>'.__FILE__.'</b> ,Function <b>'.$function.'()</b> :'.$errormsg);
	}
}
?>